Current-saving electrical igniter for gas lighters

ABSTRACT

A gas lighter wherein a filament is heated to a temperature at which it ignites a stream of gaseous fuel in response to or at least substantially simultaneously with opening of a valve which permits pressurized gaseous fuel to escape from a tank. In order to save electrical energy, the circuit of the filament is opened automatically with a delay which invariably suffices to insure the ignition of the fuel stream. Delayed opening of the circuit can be effected by mechanical means, by an electronic circuit or by a confined body of a current-conducting liquid. The valve opening member of the lighter can be provided with, directly coupled to or made independent of that part or of those parts which complete the circuit simultaneously with the opening of the valve. The lighter furnishes a flame as long as the valve remains in open position but the circuit of the filament is opened with a fixed delay following completion of the circuit to thereby insure that the consumption of electrical energy takes place only during that interval which is needed to heat the filament to a temperature at which the fuel stream is ignited.

United States Patent [191 Lambert CURRENT-SAVING ELECTRICAL IGNITER FOR GAS LIGHTERS [75] Inventor: Jacques Lambert, Paris, France [73] Assignee: Flaminaire Marcel Quercia, Paris,

. France [22] Filed: Feb. 2, 1971 21 Appl. N01; 111,983

Primary Examiner-Edward Favors Attorney-Michael S. Striker 1 3,730,670 [451 May 1,1973

[57] ABSTRACT A gas lighter wherein a filament is heated to a temperature at which it ignites a stream of gaseous fuel in response to or at least substantially simultaneously with opening of a valve which permits pressurized gaseous fuel to escape from a tank. In order to save electrical energy, the circuit of the filament is opened I automatically with a delay which invariably suffices to insure the ignition of the fuel stream. Delayed opening of the circuit can be effected by mechanical means, by an electronic circuit or by a confined body of a current-conducting liquid. The valve opening member of the lighter can be provided with, directly coupled to or made independent of that part or of those parts which complete the circuit simultaneously with the opening of the valve. The lighter furnishes a flame as long as the valve remains in open position but the cir-. cuit of the filament is opened with a fixed delay following completion of the circuit to thereby insure that the consumption of electrical energy takes place only during that intervalwhich is needed. to heat the filament to a temperature at which the fuel stream is ignited. a

2 Claims, 8 Drawing Figures Patented May 1, 1973 3,730,670

3 Sheets-Sheet l INVENTOH TAcQua M0 8547 BY 11/40! f/Zub ATTORNEY Patented May 1, 1973 3,730,670

3 Sheets-Sheet 2 Z04a- F6 2/ 1 LL ,1 7:16.? v 0 1 3 J06 Ji 5 INVENTOR Tums; Ma arr ATTORNEY Patented May 1, 1973 3 Sheets-Sheet I5 INVENTOR .4mm m" Am CURRENT-SAVING ELECTRICAL IGNITER FOR GAS LIGHTERS BACKGROUND OF THE INVENTION The present invention relates to lighters in general, and more particularly to improvements in pocket lighters or table lighters which utilize gaseous fuel. Still more particularly, the invention relates to improvements in table lighters or pocket lighters of the type wherein a stream of gaseous fuel issuing from a tank in response to the opening of a normally closed shutoff valve is effected by a filament or analogous igniting means which is in circuit with an energy source and is heated to incandescence or to a temperature at which the fuel is ignited on completion of the circuit.

As a rule, the circuit contains a normally open switch which is closed in response to actuation of a valveopening member or trigger so that the filament begins to glow at a time when a stream of fuel issues from a burner which receives such fuel from the tank by way of the normally closed valve. In accordance with a presently known proposal, savings in electrical energy are to be achieved by opening the circuit of the filament as soon as or shortly after the stream of gaseous fuel issuing from the burner is ignited. Thus, the switch is to open before the trigger permits or causes the valve to seal the fuel tank from the burner. This can be achieved by mounting a movable contact of the switch open, a second position in which the valve is open and the movable contact engages a stationary switch contact to complete the circuit of the filament, and a third position in which the valve is open and the switch is also open. The stream of fuel is ignited in the second position of the trigger and the latter is then moved to its third position in order to save electrical energy by opening the switch but by continuing to maintain the valve in open position for a desired interval of time. The fuel which escapes from the tank in the third position of the trigger is ignited by the flame at the burner. The movements of the trigger are controlled by the user who must be familiar with the operation of the lighter in order to make sure that the trigger leaves the second position on ignition of fuel and remains in the third position for as long as the flame is to be kept alive.

' Faulty manipulation of the trigger either causes the gas to escape without ignition or results in excessive expenditures of electrical energy.

It is also known to provide in the circuit of the filament a safety switch or auxiliary switch which is closed when the lighter is not in use and opens in response to heating by the flame to thus open the circuit. The safety SUMMARY OF THE INVENTION An object of the invention is to provide a pocket lighter or a table lighter wherein an electrically heatable igniting element serves to ignite a stream of gaseous fuel withnovel and improved means for saving electrical energy by automatically terminating the consumption of electricalenergy upon ignition of gaseous fuel but independently of the temperature of the flame or other unpredictable factors.

Another object of the invention is to provide novel and improved means for automatically opening the electric circuit in a gas lighter wherein the fuel is ignited by an element which is heatable by electric current.

A further object of the invention is to provide automatic circuit opening means which occupies little room in a gas lighter, which is rugged and thus capable of repeated and frequent use, and which requires no attention or special manipulation by the user of the gas lighter.

An additional object of the invention is to provide a gas lighter with novel means which is capable of igniting a stream of gaseous fuel without any wasting of fuel and which saves electrical energy by insuring that the circuit of the current-consuming part or parts remains completed only as long as is necessary to invariably insure ignition of fuel.

A feature of the invention resides in the provision of a lighter which comprises a source of pressurized fluid fuel, a normally closed valve which is movable to an open position to thereby permit escape of a stream of fuel from the source, valve opening means actuatable by hand or by gravity to open the valve, and an electric circuit for igniting the fuel stream which issues from the source on opening of the valve. The circuit comprises a filament or an analogous igniting element which is heatable by electric current to a temperature high enough to ignite the fuel and is positioned adjacent to the path of the fuel stream, one or more batteries or an analogous source of electrical energy, normally open switch means, and switch closing means for closing the switch means substantially simultaneously with the actuation of the valve opening means to thereby temporarily complete the circuit for a predetermined interval of time which is independent of the temperature of the flame and sufficient to insure the heating of the igniting element to the temperature at which the fuel is ignited.

The circuit can be opened by returning the normally open switch means'to its open position independently of the position of the valve opening means, by placing the normally open switch means in series with second switch means which opens automatically with a fixed delay following the closing of the normally open switch means or following the opening of the valve, or by utilizing such normally open switch means which cannot remain in closed position beyond a predetermined interval of time. i i

The novel features which are considered as characteristic of the invention are set forth in particular in the BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a schematic partly side elevational and partly vertical sectional view of a gas lighter having automatic circuit opening means which embodies one form of the invention;

FIG. 2 is a diagram of the electric circuit in the gas lighter of FIG. 1;

FIG. 3 is a fragmentary vertical sectional view of a gas lighter which embodies modified circuit opening means;

FIG. 4 is a fragmentary vertical sectional view of a third gas lighter embodying circuit opening means which constitutes a first modification of the means shown in FIG. 3;

FIG. 5 is a fragmentary vertical sectional view of a fourth gas lighter embodying circuit opening means which constitutes a second modification of the means shown in FIG. 3;

FIG. 6 is a schematic vertical sectional view of a fifth gas lighter embodying further circuit opening means;

FIG. 7 illustrates the structure of FIG. 6 but showing the electric circuit in closed or energized condition; and

FIG; 8 is a vertical sectional view of a sixth gas lighter embodying circuit opening means which constitutes a modification of the means shown in FIGS. 6 and 7.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring first to FIG. 1, there is shown a pocket lighter comprising a housing H having in its top wall a first opening A for a portion of a depressible switch closing knob 4a forming part of a valve-opening lever 4 fulcrumed in the housing H, as at 4b, and having a portion 40 serving to open a normally closed shutoff valve 2 for liquefied or gaseous fuel which is stored under pressure in a source here shown as a tank 1. The valve 2 opens in response to depression of the knob 4a in the direction indicated by the arrow whereby a projection 4d of the lever 4 stresses a leaf spring 6 which tends to maintain the valve 2 in closed position by biasing the lever 4 in a counterclockwise direction. The valve 2 admits gaseous fuel to a burner 3 which is adjacent to an opening B of the housing H and is mounted close to an igniting element or filament 7 forming part of an electric circuit which is shown in FIG. 2. The circuit includes a normally open switch 9 having a movable contact 9a on the lever 4 and two fixed contacts 9b, 9c which are engaged by the movable contact 9a in response to depression of the switch closing knob 4a. The circuit further includes a source 8 of electrical energy (e.g., one or more batteries or cells) which is removably installed in the housing H.

Briefly stated, the operation of the lighter is as follows: When the user applies finger pressure against the knob 4a, the lever 4 pivots in a clockwise direction and its portion 4c opens the valve 2 while the projection 4d stresses the return spring 6. The valve 2 allows a stream of gaseous fuel to flow into and from the burner 3. At the same time, the switchl9 completes the circuit so that the filament 7 is heated to incandescence and ignites the stream of gaseous fuel. The resulting flame is accessible in or extends outwardly through the opening B of the housing H. The fuel continues to burn-as long as the knob 4a remains in its depressed position. When the pressure upon the knob is relaxed or terminated, the spring 6 dissipates energy and returns the lever 4 to the position of FIG. 1 in which the valve 2 is closed and the switch 9 is open.

In accordance with a feature of the invention, the circuit of FIG. 2 comprises means for automatically disconnecting the filament 7 from the energy source 8 after elapse of a predetermined interval following the closing of switch 9 by the lever 4. This brings about savings in electrical energy and prolongs the useful life of the filament 7 without in any way affecting the utility of the lighter. The filament 7 is disconnected from the energy source 8 with a predetermined delay which need not and preferably cannot be changed by the user and which is independent of the length of the interval during which the valve 2 remains open and also independent of the intensity of heat produced by the flame but long enough to insure the ignition of the fuel stream issuing from the burner on opening of the valve 2.

The circuit of FIG. 2 comprises two transistors 10 and 12 whose collectors are connected to the positive terminal of the filament 7. The emitter of the transistor 10 is connected with the positive pole of the energy source 8 by way of a diode 11, and the emitter of the transistor 12 is connected to the base of the transistor 10. The base of the transistor 12 is connected with the negative terminal of the filament 7 by way of a resistor 13 and by a time-delay or retarding unit here shown as an R-C link having a resistor 14 and a capacitor 15. The R-C link 14, 15 is connected in parallel with the resistor 13. A diode 16 is connected in parallel with the resistor 14 and a resistor 17 is connected between the base of the transistor 12 and the positive pole of the energy source 8. The circuit of FIG. 2 further comprises a resistor 18 which is connected between the emitter of the transistor 10 and the negative terminal of the filament 7. The switch 9 is connected between the negative terminal of the filament 7 and the negative pole of the energy source 8. The length of the interval during which the circuit of the filament 7 remains completed depends on the time constant of the R-C link 14, 15.

The arrangement is preferably such that the time required for a discharge of the capacitor 15 is less than the time required for charging. The charging time corresponds to the length of interval during which the circuit of the filament 7 remains completed. The transistors 10, 12 can be said to constitute a second switch which is closed on closing of the switch 9 and opens the circuit with a predetermined delay (required to charge the capacitor 15) irrespective of the fact that the switch 9 remains closed.

The switch 9 is preferably a two-way switch having a further contact 9d which is engaged by the movable contact 9a when the latter assumes the open position shown in FIG. 2. The contact 9d is connected with the base of the transistor 12 by way of a resistor 19. The switch 9 completes the circuit 19-1344, 15-16 when its movable contact 9a engages the contact 9d. At the the next use. The resistor 19 insures that the lighter isready for use as soon as the knob 4a returns to the idle position shown in FIG. 1.

Instead of relying on electrical time delay and circuit opening means, the circuit of the filament 7 can be opened by mechanical means of the type shown in FIG. 3. This lighter comprises a two-piece valve-opening device including a depressible knob 104a which is biased to the illustrated idle position by a helical return spring 106 and a lever 104 which is pivotable in the housing of the lighter and has a longer arm extending into the path of movement of the knob 104a and a shorter arm which opens the normally closed valve 102 to admit a stream of gaseous fuel into the burner 103 when the knob 104a is caused to dwell in the depressed position. The filament 107 is adjacent to the burner 103 which can be lifted toward the opening 100B in response to opening of the valve 102.

The electric circuit which includes the filament 107 is much simpler than the circuit of FIG. 2; it further comprises an energy source 108 in series with the filament 107 and a normally open switch 109. The latter is closed in response to depression of the knob 1040 but can open independently of the knob, i.e., the switch 109. remains closed for a predetermined interval of time which suffices to heat the filament 107 to incandescence but need not be as long as the interval during which the knob 104a dwells in the depressed position if the user continues to exert on the knob a pressure in the'direction indicated by the arrow in order to maintain the valve 102 in open position.

The switch-closing mechanism of the lighter shown in FIG.-3 comprises a switch closing member which 'is movable from the first position shown in FIG. 3 to a second position in response to depression of the knob 104a. The mechanical time delay means which returns the member 20 to the first position to thereby permit opening of the switch 109 after elapse of a predetermined interval which is long enough to, insure satisfactory heating of the filament 107 and the ignition of fuel stream which issues from the burner 103 comprises a resilient element here shown as a helical spring 21. The spring 21 is mounted in the cylinder of a braking device which furthercomprises a piston 24 reciprocable in the cylinder 25 under and against the action of the spring 21. The cylinder 25 is pivoted to the housing of the lighter, as at 26, and is biased by a second resilient element here shown as a leaf spring 27 which tends to pivot the cylinder in a counterclockwise direction, as viewed in FIG. 3. A stationary displacing cam 23 is mounted in the lighter housing adjacent to the path of movement of the switch closing member 20 openings through which air escapes from the upper chamber of the cylinder 25.

The filament 107 ignites the fuel stream practically simultaneously with the opening of the valve 102 and the flame is maintained as long as the knob 104a remains in depressed position. When the user relaxes the pressure upon the knob 104a, the spring 106 expands and the knob returns to the illustrated inoperative or starting position. The motion transmitting shoulder 22 is then located at a level above-the top face of the valve closing member 20 whereby the leaf spring 27 can pivot the cylinder 25 in a counterclockwise direction to return the top face of the member 20 into the path of movement of the shoulder 22. The lighter is then ready for the next use.

The lighter of FIG. 3 is operated as follows:

When the user depresses the knob 104a, the lever 104 opens the valve 102 so that the burner 103 receives a stream of gaseous fuel from the tank, not shown. The knob 104a stresses the return spring 106 and its shoulder 22 depresses the member 20 which moves its conical portion against the cam 23 and is caused to pivot with the cylinder 25 about the axis of the pin 26 to stress the leaf spring 27 and to close the switch 109 which completes the circuit of the filament 107. The latter is heated and ignites the stream of gaseous fuel issuing from the burner 103. p p

, As the head 20 pivots in response to engagement with the cam 23, its top face moves laterally and away from the shoulder 22 of the knob 104a so thatthe spring 21 in the cylinder 25 is free to expand. The rate from the first to the second position and causes the I head of the member 20 to close the switch 109 when i the knob 104a reaches its operative position, namely,

that position in which the lever 104 is about to open the valve 102. The member 20 pivots the cylinder 25 in a clockwise direction to stress the leaf spring 27 whereby the top face of the member 20 moves away from the path of a motion transmitting shoulder 22 of the knob 104a so that the spring 21 is free to expand and to lift the member 20 in order to permit opening of the switch 109 with a delay which is determined by the braking device 24, 25. The expanding spring 21 must push the piston 24 toward the illustrated position, and such upward movement of the piston takes place at a speed which can be determined in advance by appropriate selection of the cross-sectional area of the opening or at which the piston 24 can expel air from the upper chamber of the cylinder 25, i.e., the head 20 rises gradually and permits the switch 109 to open with a predetermined delay which is a function of the characteristics of the braking device including the cylinder 25 and piston 24.

Once the fuel stream is ignited,the flame remains alive as long as the user continues to maintain the knob 1040 in operative position. When the return spring'106 is allowed to expand and to lift the knob 1040 to the starting position shown in FIG. 3, the leaf spring 27 is free to pivot the cylinder 25 in a counterclockwise direction so that the face of the member 20 returns into the path of movement of the shoulder 22.

The main difference between the lightersof FIGSJ and 3 is that the switch 109 can open independently of the knob 104a whereas the switch 9remains closed as long as the user continues to maintain the knob 4a in depressed position.

FIG. 4 shows a modification of the lighter of FIG. 3.

The knob 204a of the valve: opening means is reciprocable along rather than at right angles to the top wall of the lighter housing and the valve opening lever 204 is a bell crank which opens the valve 202 and simultaneously lifts the burner 203 toward the filament 207 when the knob 204a is moved in a direction to the closing member 20 is depressed to move the piston 24 toward the pivot 26 and is thereupon pivoted by the displacing cam 23 to move away from the shoulder 22 when the knob 204a is moved in a direction to the left. The switch 209 opens with a delay which is determined by the rate of speed at which the spring 21 can expand. The connection between the knob 204a and the lever 204 comprises a rod 20412 which causes the lever 204 to open the valve when the circuit is already completed and the filament is ready to ignite the fuel stream.

The parts 302, 303, 304, 304a, 304b, 306, 307, 308, 309 of the lighter shown in FIG. are analogous to the similarly referenced parts of the lighter of FIG. 4. The switch 309 is closed in response to leftward movement of the knob 304a whose shoulder 322 entrains switch closing member 320 having a rack 28 meshing with a pinion 29 having a shaft which is movable sideways in a relatively short slot 31 provided in the lighter housing. The slot 31 is parallel with the direction of lengthwise movement of the member 320. The pinion 29 is rigidly connected with a friction wheel 30 which normally bears against friction generating shoes 32 in the lighter housing under the action of a spring 321 which urges the member 320 against the shoulder 322 of the knob 304a.

When the knob 304a is moved in the direction indicated by the arrow, the rod 304b pivots the bell crank lever 304 to open the valve 302. At the same time, the

shoulder 322 moves the member 320 which moves along the switch 309 but does not as yet complete the circuit. As the member 320 advances in a direction to the left, it moves the shaft of the pinion 29 along the slot 31 so that the friction wheel 30 moves away from the shoes 32 and is free to rotate with the pinion 29 in response to lengthwise movement of the rack 28. The displacing cam 323 thereupon engages an inclined face of the member 320 and pivots the member 320 about the axis of the pinion whereby the member 320 closes the switch 309 and its right-hand end face slides off the shoulder 322. Thus, the spring 321 is free to pull the member 320 back to the position shown in FIG. 5. However, as the spring 321 begins to contract, it causes the shaft of the pinion 29 to return into the right-hand end of the slot 31 so that the wheel 30 engages the shoes 32 and opposes rotation of the pinion 29. Such rotation is necessary in order to permit a contraction of the spring 321. Thus, the braking device including the wheel 30 and shoes 32 determines the length of that interval which is required to return the member 320 to the position of FIG. 5 in which the switch 309 is permitted to open and to terminate the flow of current through the filament 307. Note the notch 320b which permits the switch 309 to open even though the member 320 bears against the underside of the knob 304a, i.e., even though the member 320 does not engage the shoulder 322.

The spring 321 is mounted in such a way that it tends to pivot the member 320 in a counterclockwise direction so that the right-hand end face of the member 320 automatically returns into the path of the shoulder 322 when the spring 306 is free to return the knob 304a to the illustrated position.

It is clear that FIGS. 3-5 merely show a few examples of mechanical means which can open the circuit of the filament upon ignition of the stream of gaseous fuel.

For example, the braking device of FIG. 3 or 4 or the braking device of FIG. 5 can be replaced with a conventional escapement mechanism similar to those used in timepieces or certain camera shutters and capable of delaying the movement ofa switch-closing member (20 or 320) to its normal position. With reference to FIG. 5, the pinion 29 can carry on'its shaft an escapement wheel which cooperates with an escapement anchor to delay return movement of the member 320 under the action of the spring 321.

It if further clear that the knob 304a of FIG. 5 can be mounted for reciprocatory movement in a direction at right angles to the top wall of the lighter housing. The member 320 is then caused to move up and down, as viewed in FIG. 5.

In each embodiment of the present invention, the valve opening means is preferably mounted in such a way that it opens the valve and admits fuel to the burner when the knob 4a, 1040, 204a or 304a is nearly fully depressed or otherwise displaced or assumes its fully depressed or displaced position. Thus, the gaseous fuel can begin to escape from the tank immediately or shortly before the filament is heated to a temperature at which the ignition of fuel takes place. With reference to FIGS. 3-5, the lever 104, 204 or 304 is preferably causedto open the respective valve immediately before the member 20 or 320 begins to pivot under the action of the cam 23 or 323 in order to close the switch 109, 209 or 309.

Referring to FIGS. 6 and 7, the switch 409 has two contacts 34, 55 installed in the chamber 33a of an hour-glass shaped receptacle 33 which includes a second chamber 33b and confines a body of mercury or another current-conducting liquid. In the horizontal position of the housing 400H as shown in FIG. 6, the body of liquid partially surrounds the contact 35 but extends to a level below the contact 34, i.e., the switch 409 is open. If the housing 400I-I is moved to the upright position of FIG. 7, the body of liquid conducts current between the contacts 34, 35 and the switch 409 is closed to complete the circuit of the filament 407 and energy source 408. The valve openingmember 404 is a weight which is actuated by gravity to open the valve 402 and the filament 407 ignites the stream of gaseous fuel which issues from the tank40l to flow into and from the burner 403. The switch 409 opens automatically after a predetermined interval of time which is determined by the positioning of contacts 34, 35, by the quantity of liquid in the receptacle 33, and by the dimensions of the flow-restricting passage 33c between the chambers 33a, 33b of the receptacle 33.

In the embodiment of FIGS. 6 and 7, the switch 409 is installed in a table lighter and the housing 400I-I is to be at leastpartially inverted by turning it through an angle of about degrees in order to close the switch 409. However, it is equally within the purview of the invention to close the switch 409 in response to an angunot simultaneously contact the terminals 35 and 34. A

spring 404e insures that the member'404 permits closing of the valve 402 when the housing 400H is held in the position shown in FIG. 6.

In the embodiment of FIG. 8, the valve opening member 504 is connected with the receptacle 33 in such a way that the latter is caused to change its orientation. from the position of FIG. 8 to a position corresponding to that of FIG. 7 in response to opening of the valve 402 and that the receptacle 33 remains in the inverted position as long as the valve 402 admits fuel to the burner 403. The receptacle 33 is caused to reassume the position of FIG. 8 when the member 504 is released but such change in orientation does not cause a renewed closing of the switch 409. As mentioned above, the switch 409 is preferably designed in such a way that the liquid contacts the terminal 34 simultaneously with the terminal'35 only when the liquid flows from the chamber 330 into the chamber 33b.

The means for inverting the receptacle 33 in response to downward movement of the valve opening member 504 comprises a toothed rack 504f which shares all movements of the member 504 and a diskshaped carrier 504g which supports the receptacle 33 and is rotatably mounted in the housing 500I-I. The carrier 504g has teeth which mesh with the teeth of the solutely necessary to invariably heat the filament to a temperature which suffices to ignite the fuel. This brings about substantial savings in electrical energy and insures longer useful life of the filament.

- The length of the interval during which the circuit remains completed can be determined by the manufacturer with a reasonably high degree of accuracy, either by appropriate selection of the time constant of the R- C link 14, (FIGS. l-2), of the braking action of the devices shown in FIGS. 3-5 or of the rate of flow of current-conducting liquid. through the flow restricting passage 33c (FIGS. 68).

Another important advantage of the improved lighter is that the parts of the means which automatically opens the circuit occupy little room and can stand long periods of frequent use. The circuit opening means are sufficiently rugged and reliable to warrant their use in all kinds of gas lighters wherein the fuel stream is ignited by a filament or other igniting means which is ready to ignite a fuel stream in response to at least temporary completion of an electric circuit.

Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can, by applying current knowledge, readily adapt it for various applications without omitting features which fairly constitute essential characteristics of the generic and specific aspects of my contribution to the art and, therefore, such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the claims. W

What is claimed as new and desired to be protected by Letters Patent is set forth in the appended claims.

I claim:

1. In a lighter, a combination comprising a source of pressurized fluid fuel; a normally closed valve movable to an open position to permit escape of a stream of fluid from said source; valve opening means actuatable to open said valve; and an electric circuit for igniting the stream which issues from said source on opening of said valve and comprising an igniting element heatable by electric current to a temperature high enough to ignite the fuel and positioned adjacent to the path of the stream, said igniting element comprising a filament having a first and a second terminal, said electric circuit further comprising a source of electrical energy, normally open first switch means, switch closing means for closing said first switch means substantially simultaneously with the actuation of said valve opening means to thereby temporarily complete said circuit for a predetermined interval of time which is sufficierit to ensure heating of said filament to said temperature, normally closed second switch means in series with said normally open first switch means and time-delay means for opening said second switch means after elapse of said predetermined time interval following the closing of said normally open switch means, said second switch means and said time-delay means comprising two transistors having collectors connected with one of said terminals, diode means connecting the emitter of one of said transistors with one pole of said energy source, the base of said one transistor being connected with the emitter of the other transistor, first resistor means connecting the base of said other transistor with the other pole of said energy source, an R- C link connected in parallel with said first resistor means, said link including capacitor means and second resistor means, second diode means connected in parallel with said second resistor means, third resistor means connecting the base of said other transistor with said one pole of said energy source, and fourth resistor means connected between the emitter of said one transistor and the other. terminal of said filament, said normally open switch means being connected between the other terminal of the filament and the other pole of said energy source.

2. A combination as defined in claim 1, further comprising fifth resistor means for effecting discharge of said capacitor means in response to opening of said normally open switch means. 

1. In a lighter, a combination comprising a source of pressurized fluid fuel; a normally closed valve movable to an open position to permit escape of a stream of fluid from said source; valve opening means actuatable to open said valve; and an electric circuit for igniting the stream which issues from said source on opening of said valve and comprising an igniting element heatable by electric current to a temperature high enough to ignite the fuel and positioned adjacent to the path of the stream, said igniting element comprising a filament having a first and a second terminal, said electric circuit further comprising a source of electrical energy, normally open first switch means, switch closing means for closing said first switch means substantially simultaneously with the actuation of said valve opening means to thereby temporarily complete said circuit for a predetermined interval of time which is sufficient to ensure heating of said filament to said temperature, normally closed second switch means in series with said normally open first switch means and time-delay means for opening said second switch means after elapse of said predetermined time interval following the closing of said normally open switch means, said second switch means and said time-delay means comprising two transistors having collectors connected with one of said terminals, diode means connecting the emitter of one of said transistors with one pole of said energy source, the base of said one transistor being connected with the emitter of the other transistor, first resistor means connecting the base of said other transistor with the other pole of said energy source, an RC link connected in parallel with said first resistor means, said link including capacitor means and second resistor means, second diode means connected in parallel with said second resistor means, third resistor means connecting the base of said other transistor with said one pole of said energy source, and fourth resistor means connected between the emitter of said one transistor and the other terminal of said filament, said normally open switch means being connected between the other terminal of the filament and the other pole of said energy source.
 2. A combination as defined in claim 1, further comprising fifth resistor means for effecting discharge of said capacitor means in response to opening of said normally open switch means. 